Advertisement

Advertisement

Review: A close look at the silver linings – ‘Spacious Skies’ by Richard Scorer and Arjen Verkaik

By C. G. COLLIER

David & Charles, pp 192, Pounds sterling 20

AT FIRST glance, this appears to be a straightforward, perhaps rather
old fashioned, book of cloud photographs, but it is much more than that.
The text is rich in what one might call meteorological philosophy, coupled
with enough physical insight to enhance the reader’s understanding. The
preface says: ‘This book is the work of two enthusiasts whose passion for
the sky infuses their observations and explorations with the lifeblood of
science – a sense of wonder.’

This is not overstatement. The meeting in 1984 of Richard Scorer, a
meteorologist who was a photographer, and Arjen Verkaik, a photographer
concentrating on clouds, has resulted in a collaboration that rekindles
for me that sense of wonder in nature that has encouraged so many of us
to embark upon careers in meteorology.

Thirteen chapters make the case for ‘skywatching’ as a means for understanding
what clouds can tell us about the weather, and ‘earthwatching’ which reveals
‘the bloodstream of the biosphere (which) is exquisitely evident when viewed
from space’. In the early chapters particularly, the prose occasionally
overembellishes the point to be made. For example, ‘Sky is home to our strongest
emotions, deepest thoughts to yesterday’s warm memories and tomorrow’s wildest
dreams,’ or ‘The ultimate one (transitional moments), of course, is that
moment of absolute harmony when we experience the magic of sky in our souls.’
Nevertheless, he writes much commmon sense that many professional meteorologists
need to recall from time to time.

Advertisement

Clouds may be the signatures of the physics of the atmosphere but, as
the authors note, ‘Science today compartmentalises information and sees
the subject as separate from the world and not an intrinsic part of it.’
Scorer and Verkaik lament that little credence is given simply to watching
clouds and that many users of satellite information are compelled by ‘professional
duties’ to incorporate it into numerical form for use in weather prediction
models.

While this philosophy is fascinating, and to some extent serves to highlight
the two distinct styles in the text, there is also much useful science.
This ranges from why we need more drinks on long air flights, cloud radiative
equilibrium, and conceptual models of thunderstorm airflow to clear concise
descriptions of the mechanisms of sonic and gravity waves.

Descriptions of cumulus clouds frontal and alto clouds, cumulonimbus,
ice clouds and wave clouds appear in chapters 4 to 9. Comprehensive descriptions
and spectacular photographs of optical phenomena such as sub-suns, pillars,
haloes and fog bows in chapters 10 to 12. Haboob effects, or density currents
round off the wide range of observable atmospheric features. An appendix
contains a potpourri of useful information on the physical nature of clouds
and particle sizes.

The chapters I enjoyed best describe cumulonimbus clouds ‘the grandfather
of all clouds’, severe weather and the storm environment using image time
sequences and conceptual models drawn mainly from the careful observational
studies of the American meteorologist Charles Doswell. Unfortunately, the
descriptions of fronts and cyclones is too simplistic and, strangely, the
authors fail to link the conceptual models they describe to the excellent
satellite photographs. So the chapter dealing mainly with satellite photography
is weak. For example, Scorer and Verkaik describe the pictures from the
NOAA Advanced Very High Resolution Radiometer (AVHRR) gathered from the
University of Dundee archive, but they hardly mention the data from the
geostationary satellite, Meteosat. Certainly AVHRR pictures have much higher
spatial resolution than Meteosat images and are therefore visually attractive,
but pictures from geostationary orbit add new information from their temporal
continuity. Also, while they rightly stress the importance of Channel 3
(3.7 micrometres), it is perhaps unfortunate that the authors make no mention
of the added information – for example, on the distribution of fog – generated
by adding and differencing spectral bands. They also fail to report the
importance of correcting for atmospheric absorption in quantitative use
of the imagery.

There are few mistakes in the text, although the use of ‘shelf cold
front’ to describe an upper cold front is perhaps not K K universally accepted.
The authors could improve some of the captions: for example, the fifth picture
referred to in paragraph 6.20e does not appear, and the writers also introduce
frequency channels before they define them. The use of space-view projection
for the satellite images is sometimes confusing.

Cloud images contain a wealth of information and, as this book stresses,
those data enrich our understanding of weather processes. While I feel that
it would have been better to order the chapters to provide a progression
from small-scale phenomena to large-scale systems, there is so much information
in this book that my minor criticisms should not deter amateur and professional
meteorologists alike from exploring its treasures.

For weather forecasters, it is undoubtedly true that ‘the ultimate test
of our skills comes when we are able to distinguish straightforward cloud
movement from the actual changes in shape, size and structure that are always
underway as well.’ This book should be read by all those who are curious
about the appearance of the sky, and should be mandatory reading for all
practising meteorologists.